String对象是不可改变的。如果要修改字符串而不创建新的对象，则可以使用（）类。 ["AppendFormat","BuilderString","StringBuilder","CopyString"]
电子点火系的二次侧电压较高，主要原因是（）。 ["火化塞间隙大","点火线圈性能好","高压线不易漏电","一次侧电流大"]
To increase the availability of an Advanced Replication environment， you can add a new master to a replication group without quiescing the group. This is achieved（）. ["Only when the new master site already has existing replication groups. ","By issuing a single command to create, populate, and activate the new master. ","When the master definition site is not the same for all of the master groups. ","Without impacting end users who are executing data manipulation language (DML) commands on the replicated tables."]
人民法院审理行政案件的依据是（）。 ["省人大及其常委会制定的地方性法规","自治条例与单行条例","国务院制定的行政法规","国务院各部委制定的规章"]
论述孔板流量计的工作原理？
数据挖掘技术包括3个主要部分：（）、（）、（）。
